Firefighting systems incorporating a number of nozzles, connected to water source by means of a pipe system, are well known. According to such systems, the nozzles are provided with a release mechanism, communicating with the valves or the like for allowing water to leave the nozzle if and when a fire is detected and the nozzle is actuated. Further, it is well known to use trigger rods, such rods comprising a thin-walled cavity containing a liquid. When the liquid in the cavity is heated to a certain degree, it expands and thus breaks the wall of the cavity, thus releasing the sealing effect on the valve and allowing opening of the valve.
NO 319353 discloses a protection of a rotating nozzle arranged in a house which partly surrounds the nozzle. The protection comprises a cap which is attached to the house in a releasable manner in order to form a surrounding chamber for the nozzle, where the cap comprises an opening allowing a breakable element to project axially through the cap. According to this solution it is the trigger rod forms the release mechanism which directly releases the valve inside the nozzle, also releasing the cap at the same time.
Such solution is provided with a frame containing the trigger rod, such trigger rod being in direct contact with the valve. Further, such frame projects perpendicularly out from the nozzle and is highly visible. Accordingly, when the release mechanism of the system according to NO 319353 must be changed or maintenance work is in progress, the entire, or at least branches of the system must be drained off, and then refilled with water upon completed maintenance work.
It is therefore a need to provide a nozzle which does not to any degree extend perpendicular out from the supporting wall or ceiling. Further there is a need for a nozzle having a neutral, nearly not visual and esthetical appearance. Moreover there is need for a solution where the entire system may be vented without having to close down the system or temporarily setting a nozzle, a branch or the entire system out of function.